Rotary impact tool



' Sept. 5, 1950 L. P. FOSNOT ROTARY IMPACT TOOL Filed June 24', 1946 ATTORNEY INVENTOR.

Patented epto 5, 1950 v STATE ROTARY IMPACT TOOL Application June 24, 1946, Seriai No. 678,728

12 Claims. (Cl. 192-305) This invention relates to improvements in portable power operated impact tools for setting and removing nuts and bolts by power.

The invention, while relating to tools of the character referred to, is particularly concerned with the impact clutch mechanism employed in such tools to clutch and declutch the hammer and the anvil members of the clutch and for imparting rotational hammer blows on the anvil member to tighten or loosen the nut or bolt being driven by the tool; the invention having among it principal objects the following:

To provide an impact clutch construction wherein fly-weights are pivoted on the hammer member and are swung by centrifugal force in the rotation of the hammer member into the path of abutments or jaws on the anvil member to clutch the hammer and the anvil members and to impart rotational hammer blows on the anvil member in the relative rotation of the two members and cam-means are provided on the driving member of the clutch for withdrawing the fly- Weights out of the path of the jaws to declutch the clutch immediately following each impact blow.

To have the cam-means which withdraws the fiy-weights out of the path of the jaws act on the ends of the fiy-weights opposite to the ends thereof which are moved by centrifugal force to engage said jaws;

To provide said cam-means in the form of rece'sse in the driving member and lugs on the flywfeights extend into said recesses to rotate the ha er member by the driving pressure of the drivingflmember on said lugs; and

,To provide the driving member with a shaft portion extending through the hammer member and into the anvil member between said flyweights to align and support the clutch members for relative rotation within the tool.

The invention consists further in the structural features and combinations of parts hereinafter described and claimed.

In the accompanying drawings:

Fig. 1 is a longitudinal sectional view with parts in elevation of a portable power operated impact tool containing an impact clutch construction of my invention, the upper or motor section of the tool being broken away for illustrative purposes; the section being taken on line I, ,l-;o fifjig, 2 and showing the centrifugally respo'nsive z fiy-weights Of the clutch in the path of thejaws or abutments on the anvil member of the clutch;

Fig. 2 is a transverse sectional view taken on line 2-2 of Fig. 1 showing, in broken lines, the fly-weights of the clutch out of the path of said jaws to declutch the clutch;

Fig. 3 is a similar sectional view taken on line 3-3 of Fig. 1 showing the cam-means on the driving member to withdraw the fly-weights out of the path of the jaws; and

Fig. 4 is a side elevational view of the clutch unit removed from the tool.

As shown in the drawings, the impact clutch of my invention comprises a driving member I, an anvil member 2, and an interposed hammer memher 3, all assembled in axial alignment on a clutch shaft d for relative rotation in the forward or nose end section 5 of the outer casing of the tool. The hammer member 3 is in the form of a cylindric body of the desired weight or mass and is mounted for rotation about the shaft 6 which is provided on and fixed to the driving member I. The shaft ,4 extends through the hammer member 3 and into a hollow spindle 6 on the anvil member 2 and which spindle 6 journals the anvil member 2 of the clutch device for rotation in the section 5 of the tool case as shown in Fig. 1. The spindle 6 terminals in a non-circular section 7 exterior of the tool case to mount and drive a nut or bolt engaging socket 8 releasably connected with the spindle section 1 by a spring biased detent pin 9 as shown in Fig. 1.

Mounted in the rear section ID of the tool casing is the tool motor Ii for driving the spindle 6 and the attached socket 8 through the clutch device in the operation of the tool. A fluid pressure actuated rotary motor is shown in Fig. 1 and in a motor of this type its rotor i2 and radial blades i3 are located within a cylinder l4 fixed in the tool case section I0 against rotation as shown. The motor ii is of the reversible type for setting and removing nuts and bolts by the power of the tool. The tool is provided with the desired porting and pressure fluid passage system to control the supply of fluid pressure or compressed air to the tool motor for operating it and a reversing valve (not shown) is included in the tool assembly to control the direction of rotation of the tool,

motor as Well understood in this art.

The driving member I of the clutch has a disc l5 at the upper or inner end of the shaft 4 and extending over the adjacent end of the hammer member 3. Said disc I5 is integrally or otherwise rigidly connected with the shaft 4 and has a hollow, central, hub portion 16 aligned with the shaft 4 to couple the disc IE to the lower trunnion or shaft section I! of the tool motor, there being a splined connection between the parts for directly driving the disc l from the tool motor as shown. The hub l6 and the trunnion H are supported in the tool case in suitable anti-friction bearings mounted therein as shown in Fig. l, and which bearing assembly provides a Journal to revolubly support the clutch unit within the tool case at its end opposite to the anvil member 2.

Mounted on the hammer member 3 is a pair of fly-weights l8, l8, located in chambers l9, I9, one for each fly-weight, and extending longitudinally of the hammer member on opposite sides of its axis as defined by the shaft 4 as shown in Said fly-weights I! are pivoted on the hammer member 3 on pivot pins 20 inserted therein and disposed in transverse relation to the clutch shaft 4. This permits the lower ends of the fiy-weights I8 to be swung outwardly by centrifugal force in the rotation of the hammer member into the path of abutments or jaws on the anvil member 2 to be next described. The pivot pins 20 are anchored in the hammer member 3 in any suitable manner. A sleeve or collar element (not shown) may be employed for this purpose as disclosed in the co-pending application of myselfand Walter G. Mitchell for an impact tool, said application having Serial No. 660,348, filed April 8, 1946, and owned by the same assignee as this instant application.

The anvil member 2 has a radial wall 2| opposed to the lower end of the hammer member 3 and said wall 2| is provided with a pair of upstanding or axially extending abutments or jaws 22, 25 to be engaged by the lower ends of the fly-weights It for clutching and declutching the hammer and the anvil members and for imparting a series of rotational hammer blows on the anvil member in the relative rotation of two members in the operation of the tool.

The abutments or jaws 22, 23 are disposed on the anvil member 2 in circumferentially spaced relation about the clutch axis 4 and are located adjacent to the outer periphery of the anvil wall 2| as shown in Fig. 2. Moreover, the abutments or jaws, which are substantially of the same height and integral with the anvil wall 2|, are located in the space between the opposed ends of the hammer and anvil members as shown. The chambers I9 intersect said space and the lower ends of the fly-weights l8 have integral extensions 24 to extend into said space to engage and strike, respectively, against the side surfaces of the abutments towards which the fly-weights are rotated by the hammer member in the operation of the tool.

The opposite side surfaces of the extensions 24 of the fly-weights I! are substantially flat to engage and strike, respectively, against the complementary side surfaces of the abutments or jaws 22, 23 in the reverse directions of rotation of the hammer member 2 in the operation of the tool. Hence, rotating the tool motor in the direction of the arrow in Fig. 3 enables the tool to set and tighten a nut or bolt with a right hand thread or loosen or remove one with a left hand thread, while driving the tool motor in the opposite direction reverses the action of the clutch device. The direction of rotation of the tool motor is controlled through the reversing valve hereinbefore mentioned.

Figs. 1 and 2 show in full lines the lower ends 2| of the fly-weights |l swung outwardly into the path of the Jaws 22, 22, whereas, said figures show in broken lines the positions of the lower ends of the fly-weights II when swung inwardly by the cam-means to be presently described out of the path of the abutments or jaws 22, 23 to declutch the clutch following each impact blow on the abutments by the fly-weights H3.

The abutments 22, 23 are arranged concentrically tothe clutch axis and are spaced sufficiently outwardly therefrom to permit the lower ends of the fly-weights l8 to pass the abutments for rotation of the hammer member by the driving member in the operation of the tool. Hence, the hammer member 3 when its rotation is arrested by an impact blow on the abutments may be picked up by the driving member and be accelerated so that centrifugal force will return the lower ends of the fly-weights I8 into the path of the abutments to impart a series of impacts thereon in the continued rotation of the tool motor as required for nut tightening or loosening purposes. Hence, the nut or bolt being set can be tightened to the desired tension.

The disc I5 is provided with a pair of diametrically disposed recesses 25, 25 to receive upwardly extending lugs 26 on the fly-weights |8 as shown in Figs. 1 and 3. The chambers l9 extend through the upper end of the hammer member 3 for the lugs 26 to extend into said recesses 25. It will be noted that the fly-weights l8 are fashioned with an increased width or mass at their lower ends to render them more responsive to centrifugal action.

The lugs 26 have rounded inner edges to operate with less friction on the opposed edges of the recesses 25. The latter, as shown in Fig. 3, are

alike and said recesses 25 each have a contour provided with a centrally disposed relatively deep portion a which permits the fly-weight l8 to be swung outwardly by centrifugal force into the path of the abutments 22, 23 as shown in Fig. 3. The recesses 25 are provided on opposite sides of the deep portions a with inclined or camming surfaces b, b which when the disc I5 is rotated by the tool motor relatively to the hammer member, withdraw the lower end portions 24 of the fly-weights l8 inwardly out the path of the abutments 22, 23 to declutch the clutch. The continued rotation of the disc I5 by the tool motor moves the end portions 0 of the recesses against the lugs 26 to continue the drive on the lugs 26 until centrifugal force again functions to return the fly-weights l8 into the path of the abutments. Relative rotation of the hammer and the anvil members 'to declutch the clutch occurs when the rotation of the anvil member is arrested by the engaged nut or bolt resisting the driving torque of the motor. This happens when the nut or bolt tightens against the work or when a tight nut or bolt is being loosened.

The leverage aflorded by the fly-weights It in responding to centrifugal force overcomes the rotative driving pressure of the disc Is on the lugs 25 and the fly-weights swing into the path of the abutments or jaws 22, 23 to impart hammer blows thereon in the operation of the tool. The nut or bolt being driven by the tool is indicated by 21 and the work with respect to which the nut or bolt is operated is marked 28.

The clutch device is simple in construction and operation and is compact in design to fit within the tool casing of the tool. Moreover, the cammeans herein described is interposed between The details of construction and arrangemen of parts shown and described may be variously changed and modified without departing from the spirit and scope of my invention, except as pointed'out in the annexed claims.

I claim as my invention:

1. An impact clutch comprising, relatively rotatable, axially aligned, hammer and anvil members with axially opposed wall portions having abutments on the axially opposed wall portion of the anvil member, fly-weights pivoted on the hammer member intermediate their ends and movable by centrifugal force in the rotation thereof into the path of the abutments on the anvil member to clutch the hammer and the anvil members and to impart rotational hammer blows on the anvil member at said abutments in the relative rotation of the two mem bers, a driving member having cam-means op erating on the fly-weights at their ends opposite to said abutments for driving the hammer and for withdrawing the fly-weights out of the path of said abutments to release the clutch in the relative rotation of the driving and the hammer members, and means for rotating the driving member.

2. An impact clutch comprising, relatively rotatable hammer and anvil members, the anvil member having abutments thereon, fiy-weights pivoted on the hammer member and movable by centrifugal force in the rotation thereof into the path of said abutments to clutch the hammer and the anvil members and impart rotational hammerblows on the anvil member at said abutments in the relative rotation of said two members, a driving member for rotating the hammer and having recesses therein, said fiy-weights having lugs extending into said recesses, the latter having relatively deep portions permitting the fly-weights to be moved by centrifugal force into the path of the abutments, and camming portions to withdraw the fly-weights from said abutments in the relative rotation of the driving and the hammer members, and means for rotating the driving member.

3. An impact clutch comprising, relatively rotatable hammer and anvil members, the anvil member having abutments thereon, fly-weights pivoted on the hammer member and movable by centrifugal force in the rotation thereof into the path of said abutments for clutching the hammer and the anvil members and for imparting rotational hammer blows on the anvil member at the abutments in the relative rotation of the two members, a driving member having recesses therein extending inwardly from its outer marginal portions, said fly-weights having lugs extending into said recesses, the latter having relativel deep portions to permit the flyweights to be moved by centrifugal force into the path of said abutments and camming portions on opposite sides of the deep portions to withdraw the fly-weights from the abutments in the reverse rotations of the driving member relatively to the hammer member, and means for rotating the driving member.

4. An impact clutch comprising, relatively rotatable hammer and anvil members, the anvil member having abutments thereon, fly-weights pivoted on the hammer member and movable by centrifugal force in the rotation thereof into the path of the abutments to clutch the hammer and the anvil members and to impart rotational hammer blows on the anvil member at the abutments in the relative rotation of said two members, a driving member having rigidly connected cam-means operating on the ends of said flyweights next adjacent to their pivots in a plane substantially normal to the axis of rotation of the hammer member and parallel to said pivots to drive the hammer and to withdraw the flyweights from the abutments to release the clutch in the relative rotation of the driving and the hammer members, and means for rotating the driving member.

5. An impact clutch comprising, hammer and anvil members rotatable relatively to each other about a common axis, said anvil member having abutments thereon, fly-weights pivoted on the hammer member on opposite sides of said axis and movable by centrifugal force in the rotation of the hammer member into the path of said abutments for clutching said members and for imparting rotational hammer blows on the anvil member at the abutments in the relative rotation of the two members, driving means acting on the ends of the fly-weights next adjacent to their pivots for rotating the hammer member and for withdrawing the opposite ends of the fly-weights from the abutments in the relative rotation of the driving means and the hammer member, and means for rotating said driving means.

6. An impact clutch comprising, hammer and anvil members rotatable relatively to each other about a common axis, said anvil member having abutments thereon, ily-weights pivoted on the hammer member intermediate their ends in transverse relation to said axis and having end portions extending above and below the hammer member, said fly-weights having their lower ends movable by centrifugal force in the rotation of the hammer member into the path of said abutments, a driving member acting on the upper ends of the fiy-weights for rotating the hammer member and for withdrawing the lower ends of the fly-weights out of the path of said abutments in the relative rotation of the driving and the hammer members, and means for rotating th driving member.

'7. An impact clutch comprising, hammer and anvil members rotatable relatively to each other about a common axis, said anvil member having abutments thereon, said hammer member having longitudinally extending chambers therein on opposite sides of said axis, fly-weights pivoted intermediate their ends on the hammer member in said chambers towards the upper ends thereof in transverse relation to said axis and movable by centrifugal force in the rotation of the hammer member into the path of said abutments, a driving member having cam-means operable on said fiy-weights above said cham bers to withdraw the same out of the path 0! said abutments in the relative rotation of the driving and the hammer members, and means for rotating the driving member.

8. An impact wrench comprising an operative assembly of relatively rotatable hammer, anvil and driving members, said anvil and hammer having opposed end wall portions with abutments on the end wall portion of the anvil member, fly-weights pivoted on the hammer member and movable by centrifugal force in the rotation thereof into the path of the abutments on the anvil member to clutch the hammer and'the anvil members and to impart rotational hammer blows on the anvil member at said abutments in the relative rotation of the hammer and anvil members, and cam-means rigidly and operably r 7 connected with said driving members and engaging said fly-weights for driving said hammer and for withdrawing the fly-weights out of the path of said abutments by the torque of the driving member upon continued rotation thereof to release the clutch in the relative rotation of the driving and the hammer members.

9. An impact wrench comprising an operative assembly of relative rotatable hammer, anvil and driving members, said hammer and anvil members having opposed end wall portions with abutments on the end wall portion of the anvil member, fly-weights pivoted intermediate their ends on the hammer member, the ends of the fly-weights on the sides of the pivots adjacent to the anvil member being movable by centrifugal force in the rotation of the hammer member into the path of said abutments to clutch the hammer and the anvil members and to impart rotational hammer blows to the anvil member at said abutments in the relative rotation of the hammer and anvil members, power means for rotating said driving member, and cammeans rigidly connected with the driving member and operating on the ends of the flyweights opposite to the ends thereof engageable with said abutments for driving said hammer, said cam-means having means enabling the flyweights to be moved by centrifugal force into the path of said abutments and co-acting inclined means to withdraw the fly-weights by the torque of the driving member out of the path of said abutments to declutch the anvil and hammer members following each impact blow of the fly-weights on the abutments.

10. An impact clutch comprising relatively rotatable, axially aligned, hammer and anvil membars with axially opposed end wall portions having abutments on the end wall portion of the anvil member, centrifugally movable members carried on the hammer and movable by the centrifugal force in the rotation thereof into the path of the abutments on the anvil member to clutch the hammer and the anvil members and to impart rotational hammer blows on the anvil,

member at said abutments in the relative rotation of the two members, a driving member for said hammer, and cam-means rigidly and operablyvconnected with said driving member and engaging the impacting members opposite to said abutments for driving said hammer and for withdrawing the impacting members out of the path of said abutments to release the clutch in the relative rotation, of the driving 'and hammer members.

11. An impact clutch comprising, relatively rotatable, axially aligned, hammer and anvil members with axially opposed wall portions having abutments on the axially opposed wall portion of the anvil member, fly-weights pivoted on the hammer member intermediate their ends and movable by centrifugal force in the rotation thereof into the path of the abutments on the anvil member to clutch the hammer and the anvil member and to impart rotational hammer blows on the anvil member at said abutments in the relative rotation of the two members, the portion of each of the fly-weights on the side of the pivot thereof adjacent the anvil abutments being of greater extent than the portion thereof on the opposite side of the pivot, a driving member having cam-means operating on the flyweights at their ends opposite to said abutments for driving the hammer and for withdrawing the fly-weights out of the path of said abutments to release the clutch in the relative rotation of the driving and the hammer members, and means for rotating the driving member.

12. An impact clutch comprising relatively rotatable hammer and anvil members, the anvil member having abutments thereon, fly-weights pivoted on the hammer member intermediate their ends and the portions thereof on the side of the pivots adjacent the anvil abutments being movable outwardly by centrifugal force in the rotation thereof into the path of said abutments for clutching the hammer and the anvil member at the abutments in the relative rotation of the two members, a driving member having recesses therein extending inwardly from its outer marginal edges, the fly-weight portions on the side of the pivots opposite. to

the abutments being received within said recesses and there engaging said driving member, said recesses having relatively deep portions to permit the fly-weight portions on the side of the pivots opposite to the abutments to be moved inwardly by centrifugal force as the. fly-weight portio'ns on the abutment side of the pivots are moved outwardly thereby and also having a camming portion aifiacent the deep portion and engageable with the fly-weight portion opposite the abutment to pivot said fiy-weights and to withdraw the same from the abutments upon relative rotation between the hammer and anvil member upon impact,'and means for rotating the driving member.

I LOUIS P. FOSNOT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Patent No. 2,520,920 September 5, 1950 Certificate of Correction LOUIS P. FOSNOT It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 7, line 1, for the Word members read member;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office.

.Signed and sealed this 28th day of November, A. D. 1950.

THOMAS F. MURPHi,

Assistant Oommku'oner of Patents. 

